During a manual operation on an affected area, the surgical incision must be held open so that the surgical field can be maintained and the surgeon can reach the affected area, because the force generated at the surgical incision acts in such a direction as to close the surgical incision. Maintaining the surgical field in a good condition makes it possible, for example, to reduce the operation time, to improve the safety, and to reduce fatigue of the operator (surgeon).
In a common method for holding a surgical incision open, surgical assistants hold rod-shaped medical devices with hooked front ends (see, for example, Non Patent Literature 1) and pull, by hand, the medical devices with the front ends hooked on the surgical incision site (hereinafter, this method will be referred to as “the method of holding the surgical incision open by hand”).
Other methods include using retractors whose front ends are hooked on the surgical incision site and which are held with an articulated arm extending from a pole (see, for example, Patent Literatures 1 and 2); and using retractors whose front ends are hooked on the surgical incision site and which are held with a support ring, an arm, and a pole (see, for example, Patent Literature 2 and Non Patent Literature 3) (hereinafter, these methods will be referred to as “the method of holding the surgical incision open with arm support type retractors”).
Further proposed methods include providing a retractor including in-body-side and out-body-side ring members fixed on both peripheral edges of the opening of a tubular flexible sleeve and bringing the outer surface of the flexible sleeve of the retractor into contact with the surgical incision site (see, for example, Patent Literature 3); and providing a retractor made of a rectangular elastic sheet, winding the retractor into a small-diameter roll with its beginning and terminal ends slidable relatively to each other, inserting the small-diameter roll into the surgical incision by hand, and then releasing the roll from hand so that the roll expands in diameter due to the elastic force to widen the surgical incision (see, for example, Patent Literature 4) (hereinafter, these methods will be referred to as “the method of holding the surgical incision open with an independent type retractor”).